The present invention relates to semiconductor devices, and in particular, isolating electric paths in semiconductor device packages.
A semiconductor device includes one or more functional units that are implemented in semiconductor chips. For example, the semiconductor device can include a logics unit, such as an application specific integrated circuit (“ASIC”), and a memory unit, such as a dynamic random access memory (“DRAM”). The logics unit and the memory unit can be implemented in two separate semiconductor chips or embedded in a single semiconductor chip. The semiconductor device can also include a test unit to test the memory unit or the logics unit. The test unit can be implemented in a separate chip, or embedded in the same chip that includes the memory unit or the logics unit, or both.
The semiconductor device is packaged in a device package that includes electric paths through which the functional units communicate with each other and with external devices. The device package also has package pins that are configured to connect the semiconductor device to the external devices to receive input signals or transmit output signals. The device package can be a single-chip carrier that includes a single chip in which the entire semiconductor device is implemented; or the device package can be a multi-chip carrier that includes multiple semiconductor chips, each of which implements one or more functional units of the semiconductor device. In the single-chip or multi-chip carriers, the package pins are implemented by external pads. Alternatively, the device package can include a printed circuit board (“PCB”) with one or more chip carriers and the package pins are implemented by standard board connectors.
The semiconductor device package can include one or more shared package pins. A shared pin is connected to multiple functional units that communicate with external devices through the same shared pin. For example, in an application specific semiconductor device, a shared package pin can be used alternately by a logics unit and a memory test unit.
The semiconductor package can also include a package pin that is connected to an internal electric path through which two functional units communicate with each other within the semiconductor device. For example, a functional unit can have an internal input that alternately receives signals from another functional unit within the same package and from an external device through the package pin.